FIG. 5 shows a conventional LED lamp in a sectional view (see Patent Document 1 for example). The LED lamp X illustrated in the figure includes a substrate 91 in the shape of an elongated rectangle, a plurality of LEDs 92 mounted on the substrate 91, a tube 93 accommodating the substrate 91, terminals 94, and a circuit 95 for lighting the LEDs 92. The substrate 91 is formed with a wiring (not shown) that electrically connects the LEDs 92 and the terminals 94 to each other. When the terminals 94 are fitted into insertion ports of sockets of a general-use fluorescent lighting fixture, the LEDs 92 can be turned on. Since LEDs 92 have lower power consumption and a longer life, the use of LED lamp X as a substitute for a fluorescent lamp is expected to provide advantages in terms of the cost and environment.
The general-use fluorescent lighting fixture herein refers to lighting fixtures commonly used for interior lighting as the main application, and more specifically, lighting fixtures which use, for example in Japan, a commercial 100-volt power supply and to which a JIS C7617 straight-tube fluorescent lamp or a JIS C7618 circular fluorescent lamp can be attached.
Fluorescent lamps emit light from the entire circumference of the tube. In contrast, in the LED lamp X, the light from the LEDs 92 have a relatively high directivity. Therefore, depending on the orientation of the LED lamp X in the state attached to a fluorescent lighting fixture, a desired region may not be properly illuminated with light.
Patent Document 1: JP-U-6-54103